Flooding Treatment Research Articles

Atrazine residues in flooded and nonflooded soil and effects on soybean

AbstractAtrazine applied at planting is commonly used for weed control in corn. With global climate change causing an increase in river flooding in the United States over the past decade, producers need information to determine the best course of action in flooded fields treated with atrazine into which they wish to immediately plant soybean. Studies were designed to understand the effect of flooding on atrazine residual activity including atrazine concentration, soybean injury, and soybean yield. In 2012, soybean yield in flooded treatments was reduced by prior atrazine application. In 2014, soybean injury was <10% in all plots, and nonflooded, atrazine-treated soils had yields equal to the nontreated. Findings from this research indicated that it is possible for producers to consider replanting soybean after atrazine application, with appropriate changes to product labeling.

Seedling Submergence Tolerances Accurately Predict Riparian Tree Species Distributions: Insights to Help Design Environmental Flows

Quantification of flooding thresholds that govern species distributions on microtopographic gradients in floodplains can help design environmental flows, but the multiple correlated dimensions of flooding such as frequency, depth, duration, and timing are a challenge. We postulated that species distributions are limited by the most stressful combination of flooding dimensions when the plants are in their most susceptible developmental stage. To test this idea, we measured survival of young seedlings in pots subjected to flood treatments that completely submerged the seedlings in stagnant water with and without suspended sediments for durations of up to 6 weeks during the growing season. This measure of flood tolerance predicted floodplain distributional limits of 16 tree species with high accuracy (adj. r2 = 0.91). The strength of the result suggests that seedling ability to survive complete submergence in stagnant water for prolonged periods is an important mechanism limiting species distributions in riparian forests. We propose that environmental flows that completely submerge the seedling layer in floodplain forest with stagnant water for at least 3 weeks are likely to be more effective at eliminating invading upland species than flows that only flood the soil up to the root collars of seedlings.

Redistribution of iron oxides in aggregates induced by pe + pH variation alters Cd availability in paddy soils

In this study, the effect of unstable pe + pH levels on the transformation of Fe oxides in different-sized soil fractions and its impact on Cd speciation were explored. Paddy soil samples collected from two locations in China were cultivated for two months under one of four pe + pH conditions: flooding + N2 (T1), flooding (T2), 70% water holding capacity (T3), and 70% water holding capacity + O2 (T4). Chemical analysis and X-ray diffraction (XRD) were used to identify the mineralogical phases and species of Fe and Cd in paddy soils. The results show that the decrease of soil pe + pH level favored the transformation of well-crystallized Fe oxides (Fec), such as hematite and goethite, into poorly-crystallized (Feo) and organically-complexed (Fep) forms. The transformation promoted the binding of Cd to Fe oxides and was primarily responsible for up to a 41.8% decrease of soil DTPA (diethylenetriaminepentaacetic acid)-extractable-Cd content. In addition, the decline in pe + pH value reduced Fe concentrations in soil particle fractions of 0.2–2-mm (17.8%–30.6%) and <0.002-mm (20.7%–31.7%) of the two flooding treatments. The decreased Fe concentrations were closely associated with less Fec contents in these same fractions and more Feo and Fep in coarser aggregates (P < 0.01). Importantly, the increase in contents of Feo and Fep in the 0.002–2 mm fraction were significantly correlated with content of Fe-/Mn-oxide-bound Cd (OX-Cd) in larger particle-size fractions (P < 0.01). Furthermore, the increasing content of OX-Cd played a crucial role in reducing DTPA-Cd content. This study demonstrates that low pe + pH values favor the transformation of crystalline Fe oxides into a poorly-crystallized and organically-complexed phase, which facilitates Cd accumulation in coarser aggregates and enhances Cd stability in paddy soils.

A Freshening Breath of Insight

A Freshening Breath of Insight

Water management affects arsenic uptake and translocation by regulating arsenic bioavailability, transporter expression and thiol metabolism in rice (Oryza sativa L.)

Water management is an economic and effective strategy to reduce arsenic (As) accumulation in rice grains, but little is known about the effect of water management on the migration and transformation of As in the soil-rice system. In this study, the effect of the continually (CF) and intermittent flooding (IF) treatments on the dynamic change of As in the rhizosphere soil-pore water-iron plaque-rice system was systematically investigated using pot experiments. The expressions of genes involved in As uptake and translocation in rice plants under different water management treatments were further examined. Results showed that the total As concentration in brown rice was increased by 50.8% in the CF treatment compared to the IF treatment, and dimethylarsinic acid (DMA) made greater contribution (from 15.5% to 29.2%) to total As increase in brown rice under the CF treatment. The CF treatment increased As bioavailability in the rhizosphere soil and soil pore water, which enhanced As uptake and transport to the xylem in rice plants by inducing the expressions of silicon transporter genes (OsLsi1 and OsLsi2) compared to the IF treatment. Moreover, the CF treatment increased As translocation from roots to shoots by reducing soil available sulfur and phytochelatins (PCs) biosynthesis and vacuolar sequestration in rice roots compared with the IF treatment. The study provides insight into the physiological and molecular mechanisms underlying As uptake and translocation in rice plants under different water regimes, which will be helpful for adopting the irrigation technique to mitigate excessive As accumulation in rice grains and associated health risk to humans.

Alternanthera philoxeroides invasion affects the soil seed bank of reed community

Biological invasion is a global environmental problem that has profound effects on the natural ecosystem. To gain in-depth understandings on how biological invasion affects the natural recovery potential of native vegetation, this study focused on the soil seed banks of reed (Phragmites australis) communities with different degrees of Alternanthera philoxeroides invasion. The soil seed banks were germinated under three light conditions (shading, natural light and supplementary light) and three water level conditions (immersed, 3 cm water flooded and 30 cm water flooded). The effects of the different degrees of A. philoxeroides invasion, light conditions, and water levels on the soil seed bank germination of reed communities were compared and analyzed. Our studies revealed that A. philoxeroides invasion had remarkable impacts on the soil seed banks of wetland reed communities during less than three years and water level and light had interaction on the effect of invasion. Under the supplementary light treatment, the number of germinating species in the non invasive soil seed bank (average 3.78 species/box) was significantly higher than that in the seriously invasive soil seed bank (average 2.22 species/box)(N = 9, P ≤ 0.05)). Under immersed treatments, A. philoxeroides invasion significantly reduced the seedling density (from average 905 seedlings/m2 without invasion to average 363 seedlings/m2 with mild invasion and 313 seedlings/m2 with severe invasion, N = 9, P≦0.05) and the species richness (from average 4.33 species /box without invasion to average 3.11 species/ box with mild invasion and 3.11 species/ box with severe invasion, N = 9, P≦0.05) of reed community soil seed banks. Under 30 cm water flooded treatment, the dominance index of the soil seed bank with severe invasion was significantly higher than that with mild invasion. Shading and flooding inhibited the seed germination from soil seed bank. We also discovered that A. philoxeroides invasion reduced the seedling density of the light-requiring species and the terrestrial species, such as E. crusgalli, which finally impairing the natural seed recovery potential of reed communities. These findings showed new lights on the invasion plant management and the native vegetation restoration.

Effects of Different Treatments with Water Management Combined with Leaf Spraying Silicon Fertilizer on Cd Accumulation in Rice

A field experiment involving eight treatments with water management combined with leaf spraying silicon fertilizer was conducted in a paddy field heavily contaminated with Cd (2.83 mg·kg-1) to study the effects of these treatments on rice growth and Cd accumulation in different rice tissues. The results showed that:① the treatments had no significant effects on rice plant height or number of tillers, but increased the biomass of brown rice by 1.7% to 25.0%. Among the eight treatments, that of water flooding during the rice maturation period plus leaf spraying silicon fertilizer (CY) resulted in the highest amount of brown rice yield. ② The treatment of conventional water management plus leaf spraying silicon fertilizer (Si) had no significant effect on the exchangeable Cd content and TCLP extractable Cd content in soil, whereas the other treatments reduced the exchangeable Cd content by 7.8%-42.6% and the TCLP extractable Cd content by 20.0%-40.8%. ③ The Si treatment could reduce the Cd content in various rice tissues, with an overall decrease of 19.0% in brown rice. The other treatments significantly reduced the Cd content in various rice tissues. The treatment of moisture during the rice maturation period plus leaf spraying silicon fertilizer (CS) resulted in the highest reduction in the Cd content in brown rice (44.0%), and was followed by the treatments of batch-type water flooding during the entire rice growth period plus leaf spraying silicon fertilizer (JX; 36.4%), and moisture during the rice pustulation period plus leaf spraying silicon fertilizer (GS; 31.8%). ④ For paddy-fields that are contaminated with Cd to medium and heavy levels, the CS and JX treatments are recommended to manage rice production in order to significantly reduce the Cd content of brown rice whilst having little effect on the rice yield.

The Submergence of the Graft Union Causes the Death of Grafted Mango Trees (Mangifera indica L.) under Flooding

The risk of flooding has increased as a result of climate change inspired by global warming. In this study, the difference in tolerance to flooding between grafted trees and seedlings was investigated in mango trees (Mangifera indica L.). Two levels of flooding treatment were established, in addition to a non-treated control. One was “30-flood,” in which trees were submerged up to 30 cm from the soil surface, and another was “10-flood,” in which trees were submerged up to 10 cm from the soil surface. Grafted trees treated with the 30-flood were submerged up to 5 cm above the graft union. Only the grafted trees in the 30-flood treatment began to decrease Fv/Fm and the root sugar content during treatment, then died after the completion of treatment. In grafted trees and seedlings alike, both flooding treatments also reduced root vigor, as determined by triphenyl tetrazolium chloride reduction tests and root starch content. However, root vigor and root starch content in grafted trees treated with the 10-flood as well as seedlings treated with both 10- and 30-flood recovered within two months after the completion of treatment, so that no significant differences were detected between the control. These results suggest that the submergence of the graft union into water causes the decline in photosynthesis of the scion first and the death of the grafted trees as a result.

English

The present work focused on evaluation of the physiological and metabolic behavior of alfalfa (Medicago sativa L., var. Siriver), when faced with two important ecosystems constraints, namely salinity and flooding-associated hypoxia. After germination, seedlings in symbiosis with Sinorhizobium meliloti were grown on different salt concentrations (0, 20 and 50 mM NaCl). At four weeks post-germination, plants were submitted to a five-day long flooding treatment and then analyzed for various physiological (growth, biomass) and biochemical (proteins, chlorophylls, ions, proline) parameters. Our results showed that when M. sativa was cultured on moderate (20 mM NaCl) or average (50 mM NaCl) salt stress, the classical mechanisms of stress response (ions and proline accumulation) are set up and the growth (FW, DW, growth of aerial parts) was moderately affected by salt. In a situation of average salt stress (50 mM NaCl), the combined salinity and short-term flooding led to an early alteration of the photosynthetic machinery and a modification of ions and proline contents in the leaves. Key words: Chlorophyll, hypoxia, legume, NaCl, proline, salinity.

Simulating water productivity of paddy rice under irrigation regimes using AquaCrop model in humid and semiarid regions of Iran

Rice production in the world is heavily dependent on water. Therefore, increasing in water productivity with appropriate irrigation management is necessary. Simulation models that illustrate the effects of water on crop growth can apply to optimize water productivity and improve farm irrigation management. This study was conducted to simulate water productivity of paddy rice using AquaCrop model in both humid and semiarid regions of Iran. Required data for running model were gained from two field experiments: an experiment with a lowland local rice cultivar named Champa-Kamfiroozi in a semiarid climate (Kooshkak), and other experiment with two lowland local rice cultivars named Binam and Hasani in a humid climate (Rasht). Both experiments were conducted under five irrigation treatments in two consecutive years. As a result, the relative root mean square error (RRMSE) of grain yield simulation was gained between 2.28 and 15.09%. The ranges of water productivity based on transpiration (WPT) and water productivity based on evapotranspiration (WPET) as affected by irrigation treatments, in dry climate were greater than wet climate. The averages of WPT and WPET for continuous flooding in the humid (1.21 and 0.82 kg m−3, respectively) and dry (1.26 and 0.76 kg m−3, respectively) climates showed the role of evaporation losses in decreasing WP in dry climate. The highest ET was obtained in continuous flooding treatments that the amount of evaporation for dry climate was 88% higher than humid climate.

Response of clonal versus non-clonal herbs to disturbance: Different strategies revealed

Disturbance is an omnipresent selective factor that shapes plant strategies. While annual species that rely on rapid generative reproduction dominate in habitats frequently affected by severe disturbance, long-lived woody species occupy habitats where the effects of disturbance are weak. These are, however, the extremes in the disturbance gradient. Habitats under intermediate disturbance are occupied by the whole spectrum of plant strategies. In this study, we hypothesized that clonal herbs are better adapted to intermediate disturbance than non-clonal herbs because the characteristics of their bud bank and related belowground carbohydrate storage promote vegetative regeneration. In a greenhouse experiment, we tested the effects of disturbance on the survival and performance of 17 congeneric pairs of clonal and non-clonal herbs cultivated from seed. In addition to a non-disturbed control, we applied five disturbance treatments: biomass removal 2 cm above the soil surface, removal of 70 % of the aboveground biomass, late spring frost, flooding, and belowground injury. Mortality was negligible except the flooding treatment, where it was higher for non-clonal than for clonal plants. Total biomass was reduced more by the disturbance treatments for clonal than for non-clonal plants, suggesting that clonal species suffer more than non-clonal species. On the other hand, clonal plants had significantly greater total belowground biomass and R:S ratios than non-clonal plants, suggesting a strong investment in belowground organs by clonal plants. In response to disturbance, the SLA and SRL values increased in clonal plants but decreased in non-clonal plants, indicating that clonal and non-clonal plants differ in how they cope with disturbance. Although clonality is considered to be an adaptation to disturbance, our results indicate that, during the first year of life, clonal herbs are more sensitive to disturbance than non-clonal herbs, likely due to preferential investment in belowground biomass.

Evaluation of Farming Practices for Reduction of Greenhouse Gas Emission in Korean Agricultural Sector

This study was conducted to provide low carbon farming technique for greenhouse gases(GHGs) emission reduction in agriculture sector. It reviewed literatures on the characteristic of cultivation technique and its effects on carbon emission reduction. The effects of GHGs emission reduction were evaluated in agricultural land with several farming practices. In the rice cultivation technique, the irrigation water management showed good effect on GHGs emission reduction in paddy field. It also evaluated reduction efficiency of source of nitrogen supply and soil improvement. The intermittent irrigation showed 25.1% carbon reduction efficiency as compared to continuously flooded treatment. Slow release fertilizer and ammonium sulphate decreased carbon emission by 19.8% and 7.9% compared to urea, respectively. With soil amendments treatment, silicate fertilizer and zeolite reduced carbon emission 14.1% and 21.7% compared to rice straw treatment. In the upland crop cultivation technique, the efficiency of tillage management, green manure, livestock compost and nitrification inhibitor application were estimated. Substitution of 50% of nitrogen with hairy vetch showed 65.6% carbon reduction efficiency. It also showed 20.4% emission reduction with nitrification inhibitor treatment. However, GHGs emission were increased with livestock compost application. It provided basic data for reducing the GHGs emission in agriculture sector by accomplishing low carbon farming technique and policy project. Effect of farming practices on GHG emission reduction in paddy field.

Flooding Stress and High-Pressure Treatment Enhance the GABA Content of the Vegetable Soybean (Glycine max Merr.)

γ-aminobutyric acid (GABA) is the chief inhibitory neurotransmitter in the central nervous system and of substantial physiological significance to mammals. The GABA content of plants is generally low; however, it increases significantly when plants encounter stress. The present study investigates the effects of flooding stress and high-pressure processing on GABA content enrichment in the vegetable soybean (Glycine max Merr.) cultivar Kaohsiung No. 9 and potential mechanisms. Results indicate that flooding stress increased the GABA content of vegetable soybean kernels, with the possible mechanism involving the upregulation of glutamic acid decarboxylase 5 (GAD5) and aminoaldehyde dehydrogenase (AMADH) and downregulation of succinate semialdehyde dehydrogenase (SSADH). High-pressure treatment increased the GABA content through increased GAD activity. A specific combination of flooding stress, high-pressure treatment, and storage treatment enhanced vegetable soybean GABA content up to 696.6 ± 65.7 mg/100 g. Flooding treatment prior to harvesting did not cause differences in consumption quality. These results show that flooding stress and high pressure treatment can increase GABA content and enhance the functional value of the vegetable soybean cultivar Kaohsiung No. 9.

Low external input sustainable agriculture: Winter flooding in rice fields increases bird use, fecal matter and soil health, reducing fertilizer requirements

This study investigated a low-external-input sustainable-agriculture (LEISA) rice production system in the Mississippi Alluvial Valley (MAV) that applied ecological principles to create waterbird habitat and enhance soil fertility. Two production sites were selected for this study (LEISA and conventional). Each production site applied a flooded treatment and a fallow treatment to select fields during the non-growing season (November 2017- March 2018). Bird fecal matter inputs and soil microbial bacteria/activity and nutrient content were quantified and compared between fields. Significantly more % total nitrogen, % total carbon, microbial richness and activity (P < 0.05) were found in flooded LEISA than other study fields. Bird fecal matter inputs on LEISA flooded fields contributed an estimated 6.1–48.9 kg N/ha/season, whereas 1.9–14.8 kg N/ha/season were added to conventionally flooded fields. Long-term application of the unique LEISA rice farming system can reduce the need for synthetic fertilizer application by > 13 %, while increasing soil organic carbon. This case study provides a foundation for future research into the agronomic benefits of creating bird habitat in rice fields, while documenting how conservation strategies support agronomic production and sustainability to foster conservation adoption.

Extreme precipitation enhances phenolic concentrations of spinach (Spinacia oleracea)

ABSTRACT Understanding environmental impacts on crop growth and quality is essential in developing sustainable agricultural practices with climate change. Shifts are expected in precipitation, an essential component of agriculture, including increased intensity of rainfall. We examined the effect of extreme precipitation intensity on spinach (Spinacia oleracea L.) growth and quality through a manipulative greenhouse study. Water treatments produced by a rainfall simulator modeled precipitation intensity of predicted storms in a spinach-growing area in northeastern USA and were compared to a flooding only treatment. Crop growth and quality were measured using biomass and total phenolic concentration (TPC), a general indicator of quality, which impacts the appearance, flavor, and health attributes of crops. Leaves from plants receiving high-intensity precipitation had smaller biomass than leaves from a flooding treatment. Root biomass exhibited a negative relationship with TPC. Excess water increased TPC of leaves in all treatments. Higher TPC only occurred in roots of the low-intensity precipitation treatment. Findings highlight that water treatments and extreme precipitation may enhance crop quality of spinach leaves in the context of climate change, though too much water could have negative impacts on yield and require climate-adaptation strategies.

The Effects of Flood, Drought, and Flood Followed by Drought on Yield in Cotton

Cotton suffers from alternations of flood and drought in China. A lysimeter trial was conducted to investigate the responses of various cotton yield indices under water-stress treatments including, flood (five-day, eight-day), drought (10-day, 15-day), and five-day flood followed by 10-day drought, during the flowering and boll-forming stage. The results showed that the seed cotton yield was significantly (p &lt; 0.05) reduced under all water-stress treatments, while the harvest index was not affected under any treatment. Significant decreases in dry matter yield, boll number, and boll hull mass were detected under flood treatments but not under drought treatments. The percentage cotton yield losses per day induced by flood and drought were 6.22% and 2.48%, respectively. Under water stress, the associations between seed cotton yield and relevant yield indices were weakened, but yield losses were still strongly related to the decreases in dry matter yield and boll number. Flood followed by drought caused significant reductions in all yield indices except harvest index; however, the reduction was much lower than the additive reductions induced by flood and drought. These results provide bases for scheduling irrigation and drainage under climate change.

Prediction of the uptake of Cd by rice (Oryza sativa) in paddy soils by a multi-surface model

The uptake of Cd by crops from soils is predominantly determined by the concentration and speciation of Cd in soil solution, which is controlled by soil physicochemical properties such as soil pH, soil minerals and organic matter, etc. Water management significantly affects soil pH, and especially soil pH is driven to be neutral under continuous flooding treatment. In the present study, the multi-surface models (MSMs) were modified to determine Cd partitioning in soils for prediction of Cd uptake by rice grain, with multiple parameter or setup changes including: (1) soil pH was considered as variables to improve the accuracy of model prediction for paddy soils; (2) practical co-existing cation concentration and ionic strength were derived from electron conductivity to improve the universality of model. Our results suggested that the modified MSMs model provided a better prediction for the actual uptake by rice grain and a more consistent Cd distribution pattern in paddy soils.

Male and Female Plants of Salix viminalis Perform Similarly to Flooding in Morphology, Anatomy, and Physiology

Salix viminalis L., a dioecious species, is widely distributed in riparian zones, and flooding is one of the most common abiotic stresses that this species suffers. In this study, we investigated the morphological, anatomical, and physiological responses of male vs. female plants of S. viminalis to flooding. The results showed that the plant height and root collar diameter were stimulated by flooding treatment, which corresponded with higher dry weight of the stem and leaf. However, the dry weight of the underground part decreased, which might be due to the primary root having stopped growing. The little-influenced net photosynthesis rate (Pn) under flooding treatment could guarantee rapid growth of the aboveground part, while the unaffected leaf anatomical structure and photosynthetic pigment contents could ensure the normal operation of photosynthetic apparatus. Under a flooding environment, the production ratio of superoxide free radical (O2∙-) and malondialdehyde (MDA) contents increased, indicating that the cell membrane was damaged and oxidative stress was induced. At the same time, the antioxidant enzyme system, including superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX), and osmotic adjustment substances, involving proline (Pro) and solute protein (SP), began to play a positive role in resisting flooding stress. Different from our expectation, the male and female plants of S. viminalis performed similarly under flooding, and no significant differences were discovered. The results indicate that both male and female plants of S. viminalis are tolerant to flooding. Thus, both male and female plants of S. viminalis could be planted in frequent flooding zones.

Iron fractions responsible for the variation of Cd bioavailability in paddy soil under variable pe+pH conditions

Iron (Fe) in soil is closely related to cadmium (Cd) uptake by rice plants, and soil pe + pH significantly influences Fe redox behavior. This study aimed to explore the influential mechanisms of varying pe + pH conditions on the transformation of iron oxides in the rhizosphere and the subsequent effect on Cd accumulation in rice plants. A two-month pot experiment was conducted to investigate the effect of soil pe + pH on the fractions of iron oxides and formation of iron plaque (IP), as well as the effect of these changes on Cd uptake by rice plants (Oryza sativa L.). Different irrigation strategies, 70% water holding capacity (DY), continuous flooding (FL), and alternate flooding/drying weekly (AWD), were used to achieve various soil pe + pH levels. The results showed that low pe + pH conditions (under the FL and AWD treatments) were more beneficial to the transformation of crystalline iron oxides into amorphous forms in rhizosphere soil and the precipitation of IP on rice roots. The increase of amorphous iron oxides resulted in the reduction of Cd availability in rhizosphere soil by immobilizing more Cd on Fe oxides. Moreover, Cd adsorbed on rice root surfaces reacted with IP, inhibiting Cd soil-to-root transport. The two mechanisms combinatively functioned at decreasing Cd concentration in rice shoots by 14.1–33.1% at low pe + pH conditions compared to that of the high pe + pH (DY treatment). These results indicate that lowering soil pe + pH effectively reduced Cd accumulation in rice plants, probably through the immobilization of amorphous Fe oxides on Cd and sequestration of iron-plaque on Cd.

Growth of Lonicera caerulea across Fertility and Moisture Conditions: Comparisons with Lonicera villosa and Invasive Congeners

Several species of honeysuckle from Europe and Asia have proved to be invasive in North America, with substantial impacts on native ecosystems. Although shrubby honeysuckles of Eurasian origin have appeared on banned plant lists in North America and other parts of the world, cultivars of the edible blue honeysuckle (Lonicera caerulea L.) derived from Eurasian germplasm and marketed as honeyberry, Haskap, or sweetberry honeysuckle have recently been widely developed for agricultural use in North America, with little scrutiny of invasive potential in North America despite its documented invasion of the Scandinavian Peninsula in northern Europe. To gain insight into differences in growth strategies among congeners, we compared the growth of Eurasian L. caerulea with that of a closely related congener in North America [Lonicera villosa (Michx.) R. &amp; S.] and two known invasive congeners from Eurasia (Lonicera tatarica L. and Lonicera xylosteum L.). In Expt. 1, L. villosa, L. caerulea, and L. tatarica were grown in #1 nursery containers after top-dressing with Osmocote Pro 17–5–11 4-month controlled-release fertilizer (CRF) at rates of 5, 10, 15, 20, and 25 g CRF/container. Across all fertilizer treatments, L. caerulea outperformed L. villosa by a factor of two for root and shoot dry weights, although L. tatarica produced more growth than either of the others and was more responsive to increasing CRF. However, L. caerulea more strongly resembled L. tatarica in form, producing leaves of greater individual size and producing significantly taller primary stems than L. villosa, evidence for prioritization of competitive growth. In Expt. 2, plants of the same taxa plus L. xylosteum were grown communally in #20 nursery containers, followed by a period in which each container was subjected to regular irrigation, withheld irrigation (dry treatment), or inundation (flooded treatment). Plant growth differed substantially among taxa, but moisture treatments did not affect growth significantly. As in Expt. 1, plants of L. caerulea in Expt. 2 produced greater dry biomass than plants of L. villosa and resembled the invasive Eurasian honeysuckles more strongly in size and form. We conclude Eurasian L. caerulea is distinct in growth rate and morphology from North American L. villosa. In light of these findings, the ecology and competitive ability of Eurasian L. caerulea may not be well predicted by ecological observations of its closely related North American congener.